Sperm protein 17 is expressed in human nervous system tumours

Abstract

BackgroundHuman sperm protein 17 (Sp17) is a highly conserved protein that was originally isolated from a rabbit epididymal sperm membrane and testis membrane pellet. It has recently been included in the cancer/testis (CT) antigen family, and shown to be expressed in multiple myeloma and ovarian cancer. We investigated its immunolocalisation in specimens of nervous system (NS) malignancies, in order to establish its usefulness as a target for tumour-vaccine strategies.MethodsThe expression of Sp17 was assessed by means of a standardised immunohistochemical procedure [(mAb/antigen) MF1/Sp17] in formalin-fixed and paraffin embedded surgical specimens of NS malignancies, including 28 neuroectodermal primary tumours (6 astrocytomas, 16 glioblastoma multiforme, 5 oligodendrogliomas, and 1 ependymoma), 25 meningeal tumours, and five peripheral nerve sheath tumours (4 schwannomas, and 1 neurofibroma),.ResultsA number of neuroectodermal (21%) and meningeal tumours (4%) were found heterogeneously immunopositive for Sp17. None of the peripheral nerve sheath tumours was immunopositive for Sp17. The expression pattern was heterogeneous in all of the positive samples, and did not correlate with the degree of malignancy.ConclusionThe frequency of expression and non-uniform cell distribution of Sp17 suggest that it cannot be used as a unique immunotherapeutic target in NS cancer. However, our results do show the immunolocalisation of Sp17 in a proportion of NS tumour cells, but not in their non-pathological counterparts. The emerging complex function of Sp17 makes further studies necessary to clarify the link between it and immunopositive cells.

Increased levels of sperm protein 17 mRNA and circulating antibodies in periampullary carcinoma patients

“…We observed overexpression of Sp17 mRNA in 93 % (14/15) of PAC tissue specimens as compared to distant matched nonmalignant tissue specimens. Our results are in accord with earlier reports demonstrating overexpression of Sp17 in various cancers [13,[18][19][20]. Interestingly, all of the preneoplastic tissues analyzed herein showed upregulation of Sp17, suggesting that that the alteration of Sp17 may be an early event in periampullary carcinogenesis.…”

“…Lim et al demonstrated the presence of Sp17 mRNA in 17 % of myeloma bone marrow total RNA samples [23]. Similarly, Sp17 overexpression has been reported in esophageal cancer [13], primary ovarian tumors [19], oral squamous cell carcinomas [20], nervous system malignancies [18], and diffuse large B-cell lymphoma biopsies [24]. In addition to this, Gupta et al reported increased expression of Sp17 protein in dysplastic lesions, suggesting a possible relationship of Sp17 expression with early esophageal squamous cell carcinoma development [13].…”

“…Aberrant expression of Sp17 has been demonstrated in various malignancies [18][19][20]. Although the association between Sp17 and metastasis/invasion has been investigated by various research groups, the role of Sp17 in cancers is yet to be fully elucidated [6-8, 21, 22].…”

Mapping T and B cell epitopes in sperm protein 17 to support the development of an ovarian cancer vaccine

“…Sperm surface protein 17 (Sp17) is an antigenic protein highly expressed in spermatozoa, and a member of the extensively characterised cancer testis antigen (CTA) family [16][17][18][19][20][21][22]. Sp17 is composed of 151 amino acids (aa), it is highly conserved (with 94% homology between mouse and human) [21].…”

Expression of the sperm fibrous sheath protein CABYR in human cancers and identification of α-enolase as an interacting partner of CABYR-a

“…One advantage of these two CT antigens lies in their post-meiotic expression pattern, which may reduce the risk of permanent injury to the testis of patients (5). Sp17 has been reported in various malignancies (14)(15)(16). In contrast, the expression of CABYR has only been examined in brain and lung cancers (4,6).…”